Technical Details

Worm.Win32.Fipp.a is a polymorphic file infector that infects *.exe files on random folders on an infected host. It spreads in the network via open remote shares. It can infect remote hosts via open remote connections. The worm is able to detect active Windows Remote Desktop and infect remote systems. The malware does not delete system files and does not have unrecoverable destructive activity. It can connect to remote websites. It can also kill AV processes.


While infecting host system:

  • When the malware runs for the first time, it searches for
    %system32%\wmicuclt.exe and %system32%\wscript.exe
    . When found, it will infect the original files by adding malware part in the last file section (see the infection method below);
  • Creates the service "Remote Access Connection Service" under
    HKLM\System\ControlSet\Services (as well as other ControlSets).

    The "ImagePath" string will point to the infected file in %system32%\wmicuclt.exe;
  • Creates a new value under HKLM\System\Select. The value name can be "rtm" or "v". The HKLM\System\Select is used by Windows OS for storing boot information. The OS loader reads the Current/Default/failed/LastKnownGood boot configuration while loading the OS. The malware uses the registry key for storing itself or virus specific data at this location;
  • Injects code into
  • Avoids infecting the following folders:
    "Windows", "winnt", "s", "qq", "Outlook", "System Volume Information", 
    "Recycler", "Internet\Explorer", "Messenger", 
    "Common Files"
  • Looks for WOW64, SQSh, Srh access parameters if installed on the host system;
  • If a remote session is detected (to the infected host), it will try to access the remote drive by running Windows Client command "\\tsclient\$c" and will infect *.exe files. As a result, the connecting host will be infected too;
  • Infects files on the remote host
  • Maps remote drives via \\remotehost\ipc$

Remote URL:

  • The worm can connect to URLs containing the "ppift", "ppns" substrings in a website name;

When it infects the files, it does the following:

  • It searches for shared folders on the infected computer and infects all *.exe files it finds;
  • If access to a shared folder requires user credentials, it tries to brute force user accounts and passwords. These are just a few variants:
    “admin"/"678","admin"/"1qaz2wsx","user"/"1", "test"/"1", 
    and other simple password combinations for accounts or passwords such as
    "1234", "56", "qwert","letmein", "secret", "rockyou", "iloveyou", 
    "root", "super", “princess", "alpha", "Patrick", "temp", 
    . and many other buzz words;
  • When it infects a file, it appends itself at the end of the original host file, to the last section of the file. It modifies the file header by writing the "PPIF" keyword at the 0x28h offset from the beginning of the file;
  • The new file is 47,872 bytes larger than the original.

How it disables AV applications

  • When executed on the infected host, it searches for processes with the following words in the process name:
    "F-Secure", "IKARUS-GuardX", "360sd", "360Tray", "WP", "ShStatEx", 
    "Sophos AutoUpdate Monitor", "AVP","AVG_TRAY", "egui", 
    "G Data Antivirus", "BitDefender AntiVirus",
    "Trende Micro Client Framework", "kxesc", "avgnt", 
    "RAvTray", "DWIN";
  • When found, it will search for a registry entry, delete it and reboot the system immediately. After the reboot, the system will be unable to start the AV product because there is no service entry.